The invention relates to an elevator for gripping, by frictional engagement, casings for pile foundations, for example for casing pullers, with pivotably supported elevator links. The links can be opened by a motor drive through pressure-medium operated power jacks and can be locked to each other in tension with a power jack for applying the closing force.
With elevators of this kind it is possible for the associated casing puller or casing machine to be brought into a working position by sliding transversely to the borehole while the elevator links are spread open and the base frame is correspondingly open. An elevator of the kind described hereinbefore is disclosed in the German Offenlegungsschrift No. 25 15 467 which is adapted to the task of gripping a casing, situated close to a wall, by means of pivotable elevator links. To this end, a controlled cylinder is provided to assist the operation of interlocking adjoining, openable elevator links, but the said cylinder does not participate in applying the closing force. A separate tensioning cylinder, adapted to act between the non-openable elevator links, is provided to this end. The German Offenlegungsschrift No. 27 08 727 and the U.S. Pat. No. 2,684,166, relating to an elevator for soil drilling casings are part of the extended prior art.